JPH05252168A - Data link method - Google Patents

Abstract

PURPOSE:To obtain a data link method enabling plural master stations to be present and also, easy to configure a multiplex system when cyclic data communication is performed. CONSTITUTION:A data link parameter consisting of a master station number at every master station 1 or 2, the number of corresponding local stations, a local station number at every local stations 36, an output data leading address to a corresponding local station, output data size, the relative address of output data, input data leading addresses from the local stations 3-6, input data size, and the relative address of input data is inputted to the master stations 1, 2 and the local stations 3-6 in advance, and a message frame including the data addressed to corresponding plural local stations 3-6 from either the plural master stations 1, 2 when a timing is the one at which its own station performs transmission, and the message frame including the data addressed to its own station from the plural local stations 3-6 is received.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a token-bashing method between a master station and a plurality of local stations corresponding to each other.
The present invention relates to a data link method for performing constant data communication cyclically in 1.

[0002]

2. Description of the Related Art A plurality of programmable controllers having a sequence controller for controlling a sequence of a controlled object and a data link controller for cyclically communicating are positioned in a master station and a plurality of corresponding local stations. A data link is frequently used in which the master station and the above-mentioned plurality of local stations perform constant data communication cyclically at a ratio of 1: 1 by the token-bashing method.

FIG. 10 is an explanatory diagram showing the structure of a conventional data link device. In the figure, 1 to 4 are programmable controllers (hereinafter, referred to as PC
Is said). 1 is a P station positioned as a master station (hereinafter referred to as MPC1) that controls a data link.
C is a local station that performs a data link with MPC1 at a ratio of 1: 1 (hereinafter, LPC3 and LP).
It is a PC positioned as C4).

FIG. 11 is an illustration showing a schematic configuration of the PCs 1 to 4. In FIG. 11, 7 is a sequence control unit that controls the sequence of the controlled object, 8 is a data link control unit that performs cyclic communication with another PC, and 9 is a sequence between the sequence control unit 7 and the data link control unit 8. It is a common memory for reading / writing click data.

FIG. 12 shows MPC1, LPC3, and LPC.
Link input / output for cyclic communication with 4 (Data that is cyclically output from the master station to the local station is referred to as Y below, and data that is cyclically input from the local station to the master station is referred to as X below. ) Is an explanatory diagram showing an image of FIG. In FIG. 12, reference numeral 60 denotes the entire link input / output, 61 denotes the link input / output allocation state in the master station, and 63 and 64 denote the allocation states of LPC3 and LPC4, respectively.

FIG. 13 shows a link parameter 70 for actually executing the link input / output allocation shown in FIG.
It is explanatory drawing which shows the structure of. In FIG. 13, N is the number of local stations that perform data link, No is the station number of LPC3, X
adr is the start address of X that communicates with LPC3, Xs
size is the data size of X above, and Yadr is also LP.
The Y start address for communicating with C3, Ysize, indicates the Y data size. Similar information for LPC4 is also set.

FIG. 14 is a diagram showing the structure of a frame 21 of a message for performing cyclic communication, which is based on a frame structure known as a high level data link control procedure (HDLC procedure). Here, F is a flag sequence, A is a destination address, C is a control unit (command), I is an information unit, and FCS is a frame inspection sequence.

FIG. 15 shows the structure of a frame 71 for the master station to transmit output data based on the parameters of FIG. 13, where A is the destination address indicating each station of the local station, and Y is the destination address.
C represents an output (Y) command, and YD represents output data.

FIG. 16 shows the structure of a frame 72 for the local station to transmit input data based on the parameters of FIG. 13, where A is the destination address indicating the master station, XC is the input (X) command, and XD is Represents each input data.

Next, the operation will be described. In each of the PCs 1 to 4 shown in FIG. 10, a normal data link control unit 8
Acquires the parameters shown in FIG. 13 by some method before data link. For example, before cyclic communication, parameter communication is performed between the master station and each local station. Each station checks the data link range performed by each station from the information of this data link parameter, and thereafter enables cyclic communication based on this information.

Next, the data link control unit 8 of the MPC 1
Irrespective of the operation of the sequence control unit 7, the output (Y) data is read from the common memory 9 and LPC3 and LPC are read.
A series of cyclic communication is performed by outputting to PC4, inputting (X) data from LPC3 and LPC4, and writing to the common memory 9. The sequence controller 7 also accesses the cyclic data by reading / writing the common memory 9 as necessary.

Further, the data link control units 8 of the LPC3 and LPC4, conversely, input the output (Y) data from the MPC1, write to the common memory 9, and read the input (X) data from the common memory 9. Then, a series of cyclic communication is performed by outputting to MPC1. The sequence control unit 7 of the LPC3 and LPC4 performs the same operation as the sequence control unit 7 of the MPC1.

FIG. 17 shows the data link controller 8 of MPC1.
The flowchart of the processing sequence at the time of transmission / reception in is shown.
In the figure, MPC1 clears the number of local stations that perform cyclic communication (S80), reads the data output (Y) to LPC3 from common memory 9, and transmits it to LPC3 in frame 71 as shown in FIG. (S81),
The completion of reception of the frame 72 from the LPC 3 as shown in FIG. 16 is waited (S82), and when the reception is completed, the input (X) data from the LPC 3 is written to the common memory 9 (S8).
3). Next, it is checked whether or not the cyclic communication with all LPCs is completed (S84), and the next LPC is not completed.
4 is set (S85). Then, steps S81 to S85 are repeated, and when cyclic communication with all LPCs is completed, the process returns to step S80 to execute the next cycle.

FIG. 18 shows a flow chart of a processing sequence at the time of transmission / reception in the data link control unit 8 of the LPC3 and LPC4. In the figure, LPC3 waits for reception of frame 71 from MPC1 as shown in FIG. 20 (S90),
When the reception is completed, the output (Y) data of MPC1 is written in the common memory 9 (S91). Next, the data to be input (X) to the MPC 1 is read from the common memory 9 and the data shown in FIG.
A frame 72 as shown by 6 is transmitted to MPC1 (S
92), and returns to the process of step S90.

FIG. 19 shows a flow chart of a processing sequence at the time of cyclic data read / write in the sequence controller 7 of the MPC 1. In the figure, the sequence control unit 7 of the MPC 1 first writes the output (Y) data in the common memory 9 based on the sequence processing (S40),
Input (X) data is read from the common memory 9 and sequence processing is performed (S41).

FIG. 20 shows a flow chart of a processing sequence at the time of cyclic data read / write in the sequence control section 7 of the LPC3 and LPC4. In the figure, L
The sequence control unit 7 of the PC 3 and the LPC 4 firstly processes the input (X) data by the common memory 9 based on the sequence processing.
Write to (S45) and output from common memory 9 (Y)
Data is read and sequence processing is performed (S46).

FIG. 21 is an explanatory diagram showing a schematic configuration when the cyclic communication is duplicated. In the figure, 1 is a master station (MPC1) and 2 is a standby master station (MPC2). 3A and 4A are local stations (LPC 3A and LP
C4A) is shown.

FIG. 22 is an explanatory diagram showing a schematic configuration of the local stations LPC3A and LPC4A of the PC in the case of duplication. In the LPCs 3A and 4A, 7 is a sequence control unit for controlling the sequence as in FIG. 8 is MPC
1 is a data link control unit 8A that performs cyclic communication with the MPC 2 and a data link control unit 8B and 9 that performs cyclic communication with the MPC 2 are a sequence control unit and a data link control unit 1.
And a common memory 9A for reading / writing cyclic data from / to the data link control unit 2, respectively.
And a common memory 9B.

As shown in FIG. 21, two cyclic communication is performed.
The operation in the case of duplication will be described. The operation of MPC1 and MPC2 shown in FIG. 21 is similar to the operation example of that shown in FIG. 10, but in LPC3A and LPC4A,
As shown in FIG. 22, it is composed of a data link control unit 8A and a data link control unit 8B. Since each data link control unit is independent, it is similar to the operation example shown in FIG. 10, but the sequence control unit 7 has a processing sequence at the time of cyclic data read / write as shown in FIG. Be implemented.

First, the input (X) data is written to the common memory 9A and the common memory 9B based on the sequence processing (S100), and then it is checked whether the data link control unit 8A is normal, that is, MPC1 is normal. (S10
1) If normal, the output (Y) data is read from the data link control unit 8A, that is, the common memory 9A, and sequence processing is performed (S102). If the data link control unit 8A is abnormal, is the data link control unit 8B normal?
In other words, MPC2 checks whether it is normal (S1
03), if normal, the output (Y) data is read from the data link controller 8B, that is, the common memory 9B, and the sequence processing is performed (S104). If both data link control units 8A and 8B are abnormal, error processing is performed (S
105).

[0021]

Since the conventional PC-based data link is configured as described above, firstly, only one master station can exist in one data link. In order to realize the cycle, the master stations are separately transferred for the number of local stations, so the communication time is long, and more than one data link control unit is required to realize the duplex system. There was a problem.

The present invention has been made in order to solve the above-mentioned problems, and eliminates the limitation of the number of master stations, and further shortens the communication time of one cycle, thus easily realizing a multiplexing system. The purpose is to obtain a possible data link method.

[0023]

A data link method according to a first aspect of the present invention is directed to a plurality of master stations and a plurality of rosters corresponding to the master stations.
When cyclically communicating 1: 1 cyclically between Cull stations using the token-bashing method, the master station number of each master station, the corresponding number of local stations, and the number of each local station Local station number, corresponding output data start address to the local station, the output data size, the output data relative address, input data start address from the local station, the input data size, the above A step of outputting a data link parameter consisting of a relative address of input data from one of the plurality of master stations to another master station and each of the local stations in advance, and one of the plurality of master stations. A step of transmitting a message frame including data addressed to the plurality of corresponding local stations if the timing of transmitting data is checked by the local station. Serial plurality of Russia - in which the local station comprising a step of receiving the Denbun frames containing data addressed to the own station.

A data link method according to the second invention is
Between the master stations and the corresponding local stations,
When performing constant 1: 1 cyclic data communication with the Kumbashing method, the master station number for each master station, the number of corresponding local stations, the local station number for each local station, and the corresponding From the output data start address to the local station, the output data size, the output data relative address, the input data start address from the local station, the input data size, the input data relative address Data link parameters from one of the plurality of master stations to the plurality of local stations in advance, and data addressed to the own station from the corresponding master station at the plurality of local stations. Checks whether a message frame containing a message has been received, and if so, checks the stage at which the data addressed to the own station is captured and the timing at which the own station transmits The Denbun frames containing data addressed to the master station corresponding If timing is made of a step of transmitting.

The data link method according to the third invention is
A main master station, a standby master station, and a plurality of local stations are provided, and the main master station and the plurality of local stations are connected to each other.
When performing constant 1: 1 cyclic data communication using the Kumbashing method, it is checked whether the plurality of local stations are normally linked to the main master station. If they are normal, the data is transmitted from the main master station. Receives and captures a message frame containing data addressed to its own station, and if it is not normal, checks if it is normally linked to the above standby master station, and if it is normal, it is addressed to its own station sent from the above standby master station. The step of receiving and capturing a message frame including the data of the above.

[0026]

According to the first aspect of the present invention, prior to constant cyclic data communication at a ratio of 1: 1 between a plurality of master stations and a plurality of corresponding local stations by the token-bashing method, each of the stations is provided. Master station number for each master station and the corresponding
The number of local stations, the local station number for each local station, the start address of the output data to the corresponding local station, the output data size, the relative address of the output data, the local address from the local station. A data link parameter consisting of the input data start address, the input data size, and the relative address of the input data is output from any of the plurality of master stations to the other master station and each of the local stations. At any of the plurality of master stations, it is checked whether or not the transmission timing of the own station is transmitted, and if it is the transmission timing of the own station, a message frame including the data addressed to the corresponding plurality of local stations is transmitted. , A message frame including data addressed to itself is received from the plurality of local stations.

In the second aspect of the present invention, prior to constant cyclic data communication in a 1: 1 ratio between the plurality of local stations and the plurality of corresponding local stations by the token-bashing method. Master station number for each master station, corresponding number of local stations, local station number for each local station, corresponding start address of output data to the above local station, above output data size, above output Relative address of data,
A data link parameter consisting of the input data start address from the local station, the input data size, and the relative address of the input data is input to the plurality of local stations from any of the plurality of master stations. Then, the plurality of local stations checks whether or not a message frame including data addressed to the own station is received from the corresponding master station. It is checked whether the transmission timing is from the station. If the transmission timing is from the station itself, a message frame including data addressed to the corresponding master station is transmitted.

According to the third aspect of the present invention, the main master station and the plurality of local stations are arranged in a 1: 1 ratio by the token combing system.
When cyclically communicating data continuously with, check whether the multiple local stations are normally linked to the main master station, and if normal, send the data addressed to the own station sent from the main master station. A message frame containing the received message frame is received, and if it is not normal, it is checked whether it is normally linked with the standby master station. If it is normal, a message containing the data addressed to its own station transmitted from the standby master station. The frame is received and captured.

[0029]

EXAMPLES Example 1. An embodiment of the first and second inventions will be described with reference to FIGS. In the figure, the same reference numerals as those of the conventional example indicate the same or equivalent elements as those of the conventional example. The configuration of the programmable controller as the data link device is shown in FIG.
It is the same as the one described above and will not be described again.

FIG. 1 is a diagram showing the structure of a data link system according to this embodiment. In FIG. 1, 1 to 6 are
PCs that perform data links, 1 and 2 are PCs positioned as master stations (MPC1 and MPC2),
PCs 3 and 4 are positioned as local stations (LPC3 and LPC4) that perform a data link with MPC1 at a ratio of 1: 1 respectively, and 5 and 6 are local stations (LPC5 and LPC6) that perform a data link with MPC2 at a ratio of 1: 1. )
It is a PC positioned as.

FIG. 2 shows MPC1, LPC3 and LPC4.
Is an explanatory diagram showing an image of a link input / output for performing cyclic communication with and between the MPC2 and the LPC5, LPC6 for cyclic communication with each other, and 10 is the entire link input / output. Shown, 11 is MPC1
Shows the link input / output allocation status in the above, and 12 is MPC
2 shows the link input / output allocation status. 13, 1
Reference numerals 4, 15 and 16 show the link input / output allocation states of the LPC3, LPC4, LPC5 and LPC6, respectively.

FIG. 3 is an explanatory diagram showing the structure of the link parameter 20 for actually executing the link input / output allocation as shown in FIG. 2, where M is the number of master stations and MNo is MPC.
1 is the station number, L is the number of local stations that perform data link with MPC1, LNo is the station number of LPC3, Xadr is the start address of X that communicates with LPC3, Xsize is the data size of the above X, and Xofset is the frame transmitted by LPC3. The start address of X addressed to MPC1, Yadr is the start address of Y that also communicates with LPC3, Ysiz
e is the above data size of Y, Yofset is MPC
1 shows the start address of Y addressed to LPC3 in the frame transmitted by 1. Similarly, similar information for LPC4 is also set, and similar information for MPC2 is also set.

In FIG. 4, the master stations MPC1 and MPC2 use the parameters shown in FIG.
Frame 22 for transmitting output data to LPC6
In the configuration, GA is a global address indicating that it is valid for all stations, YC is an output (Y) command, DA is a source address, and YDn is output data addressed to each local station.

In FIG. 5, the local stations LPC3 to LPC6 operate as the master stations MPC1 and MPC based on the parameters shown in FIG.
In the frame 23 structure for transmitting input data to the PC 2, GA is a global address indicating that it is valid for all stations, XC is an input (X) command, DA is a source address, and XDn is an input to each master station. Represent each data.

Next, the operation will be described. In each of the PCs 1 to 6 shown in FIG. 1, the normal data link control unit 8 acquires the parameters shown in FIG. 3 by some method before the data link. For example, before cyclic communication, parameter communication is performed by the master station (MPC1), all local stations, the master station (MPC1), and the master station (MPC2). From this data link parameter information, the data link range performed by each station is checked, and thereafter, cyclic communication based on that information can be performed.

Next, the data link control unit 8 of the MPC 1
Reads the output (Y) data from the common memory 9 to the local station, outputs it to the LPC3 and LPC4, and inputs the input (X) data from the LPC3 and LPC4 regardless of the operation of the sequence controller 7. Then, the common memory 9 is written to perform a series of cyclic communication. The sequence controller 7 also accesses the cyclic data by reading / writing the common memory 9 as necessary. The MPC2 also performs similar processing. Further, the data link control units 8 of the LPC3 and LPC4, on the contrary, input the output (Y) data from the MPC1 and write it in the common memory 9, read the input (X) data from the common memory 9, and read it in the MPC1. A series of cyclic communication is performed by outputting. LPC3 and LPC4
The sequence control unit 7 also performs the same operation as the sequence control unit 7 of the MPC 1. Further, LPC5 and LPC6 also perform similar processing.

Further, the data link control units 8 of the LPC 3 and LPC 4 conversely input the output (Y) data from the MPC 1 and write it in the common memory 9, and the common memory 9
The input (X) data is read from and output to MPC1 to perform a series of cyclic communication. The sequence control unit 7 of the LPC3 and LPC4 also performs the same operation as the sequence control unit 7 of the MPC1. Also, LPC5 and LP
C6 also performs similar processing.

FIG. 6 shows a flow chart of a processing sequence at the time of transmission / reception in the data link control unit 8 of the MPC 1 for carrying out the first and second inventions. In the figure, MPC
First of all, 1 checks whether it is the transmission timing of the own station, that is, whether the own station has a baton (S30), and if it is the timing when the own station can transmit, it sends to each local station that needs to transmit. Output (Y) data to common memory 9
From the local station to transmit the frame 22 as shown in FIG. 4 (S31), and whether the frame 23 containing the input (X) data addressed to the own station as shown in FIG. 5 is received. If checked (S32) and the reception is completed, the input (X) data addressed to the own station is written to the common memory 9 (S33). Cyclic communication is realized by repeating steps S30 to S33. The MPC2 also performs similar processing.

Next, FIG. 7 shows a flow chart of a processing sequence at the time of transmission / reception in the data link control unit 8 of the LPC 3 and the LPC 4. In the figure, LPC3 or LPC4 first outputs from each master station to its own station as shown in FIG. 4 (Y).
It is checked whether the frame 22 including the data has been received (S35), and if the reception is completed, the (Y) data addressed to the own station is written to the common memory 9 (S36). Next, it is checked whether it is the timing at which the local station transmits, that is, whether the local station has a baton (S37), and if it is the timing at which the local station can transmit, the local station that needs to transmit (X ) Data is read from the common memory 9 and transmitted in the frame 23 as shown in FIG. 5 (S38). Cyclic communication is realized by repeating steps S35 to S38. Further, LPC5 and LPC6 also perform similar processing.

The cyclic data read / write processing of the sequence control unit 7 of each master station and each local station has already been described with reference to FIGS.

Example 2. Thirdly, one embodiment of the invention will be described again with reference to FIG. In the configuration shown in FIG. 1, 1 is a master station (MPC1), 2 is a standby master station (MPC2)
Positioned as 3 and 4, the local stations (LPC3 and LPC4) that perform a data link with MPC1 and MPC2 at a ratio of 1: 1 perform the operation as duplicated. In FIG. 1, the local stations LPC5 and LPC
6 is excluded.

FIG. 8 is an explanatory diagram showing an image of link input / output for duplication. 8, link input / output for cyclic communication between MPC1, LPC3, and LPC4, and MPC2, LPC3, and LPC4
Image of link input / output for cyclic communication with and, 10 indicates the entire link input / output, 11 indicates MP
Shows the link input / output allocation status in C1, 17 is M
The link input / output allocation state in the PC 2 is shown. 13,
Reference numeral 14 denotes the link input / output allocation state of the LPC3 and LPC4 with the MPC1.
Reference numeral 19 shows the link input / output allocation state of the LPC3 and LPC4 with the MPC2.

The configuration of the link parameter 20 for actually executing the link input / output allocation as shown in FIG.
This is the same as that of FIG. 3 described in the first embodiment of the second invention. The operation of the data link control unit 8 of each of the PCs 1 to 4 and the operation of the sequence control unit 7 of the master station shown in FIG. 1 are the same as those described in the first embodiment.

Next, the LP in the case of duplication using FIG.
Sequence control unit 7 of each local station of C3 and LPC4
The operation will be described. First, MPC1 and MPC2
The input (X) data to be transmitted to the common memory 9 is written to the common memory 9 based on the sequence processing (S50), and then it is checked whether the MPC1 is normally linked (S51). If the MPC1 is normal, the output (Y) transmitted by the MPC1 is sent. ) Data is read and sequence processing is performed (S52). If the MPC1 is abnormal, the standby master station MPC2 checks whether it is normal (S53), and if it is normal, the output (Y) data transmitted by the MPC2 is read and sequence processing is performed (S54). If the standby master station MPC2 is abnormal, error processing is performed (S55).

In the above-described first and second embodiments, the data link in the PC has been described, but the same effect can be obtained even if the data link is implemented by the FA controller, the personal computer or the like. Further, in the embodiment, the example in which the master station is two stations is shown.
Even if the number of master stations is two or more, a similar one can be obtained. Further, although the data link configuration is shown as a bus type, the same effect can be obtained with a loop type, star type, or the like. Similarly, although HDLC is used for the frame structure, the same effect can be obtained by using other formats.

[0046]

As described above, according to the first and second aspects of the present invention, the master for each master station is provided before the cyclic constant data communication of 1: 1 by the token-bashing method. Station number, number of corresponding local stations, local station number for each local station, corresponding start address of output data to the local station, output data size, relative address of the output data, A data link parameter consisting of the start address of the input data from the local station, the input data size, and the relative address of the input data.
Since all the master stations and the local stations are preliminarily input with the data, a plurality of master stations can exist, and the plurality of master stations can transfer data addressed to the plurality of local stations into one data. There is an effect that a message frame can be transmitted and the communication time of one cycle can be shortened.

According to the third aspect of the invention, the token-bashing method is used between the main master station and a plurality of local stations in a 1:
When cyclically performing continuous data communication with 1, check whether the above multiple master stations are normally linked to the main master station, and if they are not normal, check that they are normally linked to the standby master station. Since the message frame including the data addressed to the own station transmitted from the standby master station is received and fetched, there is an effect that a multiplexing system can be easily constructed.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a data link system according to an embodiment of the first and second inventions.

2 is an explanatory diagram of link input / output of the data link system shown in FIG.

FIG. 3 is a diagram showing data link parameters of the data link system shown in FIG.

FIG. 4 is a diagram showing a configuration of a frame of a message transmitted by the master station shown in FIG.

5 is a diagram showing the structure of a frame of a message transmitted by the local station shown in FIG.

6 is a flowchart showing an operation of transmission / reception processing of a data link control unit in the master station shown in FIG.

7 is a flowchart showing an operation of transmission / reception processing of a data link control unit in the local station shown in FIG.

FIG. 8 is an explanatory diagram of link input / output of the duplicated data link system according to the embodiment of the third invention.

9 is a flowchart showing the cyclic data read / write processing operation of the sequence controller in the local station shown in FIG.

FIG. 10 is a diagram showing a configuration of a conventional data link system.

FIG. 11 is a block diagram showing a schematic configuration of a programmable controller.

12 is an explanatory diagram of link input / output of the data link system shown in FIG.

13 is a diagram showing data link parameters of the data link system shown in FIG.

FIG. 14 is a diagram showing a structure of a message frame used in a programmable controller.

15 is a diagram showing a structure of a message frame transmitted by the master station shown in FIG.

16 is a diagram showing a structure of a frame of a message transmitted by the local station shown in FIG.

17 is a flowchart showing an operation of transmission / reception processing of a data link control unit in the master station shown in FIG.

18 is a flowchart showing the operation of transmission / reception processing of the data link control unit in the local station shown in FIG.

19 is a flowchart showing the cyclic data read / write processing operation of the sequence controller in the master station shown in FIG.

20 is a flowchart showing the cyclic data read / write processing operation of the sequence controller in the local station shown in FIG.

FIG. 21 is a diagram showing a configuration of a conventional duplex data link system.

22 is a block diagram showing a schematic configuration of a programmable controller which constitutes the local station shown in FIG. 21. FIG.

23 is a flowchart showing the cyclic data read / write processing operation of the sequence controller in the local station shown in FIG. 21.

[Explanation of symbols]

 1, 2 Master station (programmable controller) 3 to 6 Local station (programmable controller) 7 Sequence control unit 8 Data link control unit 9 Common memory 10 Link input / output area 22, 23 Message frame

Claims (3)

[Claims] 1. A master station number for each master station when cyclically performing 1: 1 cyclical data communication between a plurality of master stations and a plurality of corresponding local stations by a token-bashing method. , The number of corresponding local stations, the local station number for each local station, the start address of the output data to the corresponding local station, the output data size, the relative address of the output data, the above A data link parameter consisting of the start address of the input data from the local station, the input data size, and the relative address of the input data.
Data from one of the above master stations to the other master station and each local station in advance, and at any of the above master stations, check whether it is the timing for transmission by the own station. , A step of transmitting a message frame including data addressed to the plurality of corresponding local stations at the timing of transmission by the station, and a message including data addressed to the station from the plurality of local stations. A data link method comprising the steps of receiving a frame. 2. A master station number for each master station when cyclically performing 1: 1 cyclical data communication between a plurality of master stations and a plurality of corresponding local stations by a token-bashing method. , The number of corresponding local stations, the local station number for each local station, the start address of the output data to the corresponding local station, the output data size, the relative address of the output data, the above A data link parameter consisting of the start address of the input data from the local station, the input data size, and the relative address of the input data.
Data in advance from any of the plurality of master stations to the plurality of local stations, and a message frame including data addressed to the own station from the corresponding master station at the plurality of local stations. Is received, and if it is received, it is checked at the stage of fetching the data addressed to its own station and at the timing of its own transmission, and if it is the timing of its own transmission, the data addressed to the corresponding master station And a step of transmitting a message frame including the. 3. A main master station, a standby master station, and a plurality of local stations, wherein the main master station and the plurality of local stations are cyclically 1: 1 in a token-bashing system. When constantly communicating data for clicks, it is checked whether the plurality of local stations are normally linked to the main master station, and if they are normal, a message including the data addressed to the own station transmitted from the main master station. If the frame is received and captured, if it is not normal, it is checked whether it is normally linked with the standby master station, and if it is normal, the message frame containing the data addressed to itself and transmitted from the standby master station is received. And a data link method comprising the steps of: